for (Entry e = header.next; e != header; e = e.next) {
            s.writeObject(e.element);
        }
    }

    @SuppressWarnings("unchecked")
    @Override
    public void readExternal(final ObjectInput s) throws IOException, ClassNotFoundException {
        final int size = s.readInt();
        header = new Entry(null, null, null);
        header.next = header;
        header.previous = header;